Orbital-motion-limited theory of dust charging and plasma response

Journal Article · Wed Dec 17 00:00:00 EST 2014 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4904404· OSTI ID:1421127

Tang, Xian-Zhu; Luca Delzanno, Gian

The foundational theory for dusty plasmas is the dust charging theory that provides the dust potential and charge arising from the dust interaction with a plasma. The most widely used dust charging theory for negatively charged dust particles is the so-called orbital motion limited (OML) theory, which predicts the dust potential and heat collection accurately for a variety of applications, but was previously found to be incapable of evaluating the dust charge and plasma response in any situation. Here, we report a revised OML formulation that is able to predict the plasma response and hence the dust charge. Numerical solutions of the new OML model show that the widely used Whipple approximation of dust charge-potential relationship agrees with OML theory in the limit of small dust radius compared with plasma Debye length, but incurs large (order-unity) deviation from the OML prediction when the dust size becomes comparable with or larger than plasma Debye length. This latter case is expected for the important application of dust particles in a tokamak plasma.

• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1421127
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Vol. 21 Journal Issue: 12; ISSN 1070-664X
• Publisher: American Institute of Physics
• Country of Publication: United States
• Language: English